Average of 3-5 business days. Sometimes they're quick with responses. I've gotten a response to a ticket within 10-15 minutes before, and I messaged them back immediately and got another response within the hour. I've had a few tickets literally resolved within a day. Other times they take forever... I've seen one of my tickets go without a reply for around 2-3 weeks. I heard someone had their ticket go slightly over 2 months until they got a response. And apparently some players have had their tickets left open and never replied to ever, or just closed without being answered or resolved.
Is it possible that sometimes they have to wait for confirmation from Nimonix first? They might also have to translate the English into Korean for them to understand. This could be why it takes so long sometimes if they have to wait for an answer from Nimonix first.
Sorry, I don't forum 24/7 like you treating this like social media. Came here for help like forums are for.